From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751922AbaKDTft (ORCPT ); Tue, 4 Nov 2014 14:35:49 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.230]:8121 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751158AbaKDTfs (ORCPT ); Tue, 4 Nov 2014 14:35:48 -0500 Date: Tue, 4 Nov 2014 14:35:38 -0500 From: Steven Rostedt To: "Rustad, Mark D" Cc: "linux-kernel@vger.kernel.org" , Ingo Molnar , Andrew Morton , Jiri Kosina , Petr Mladek , "H. Peter Anvin" , Thomas Gleixner , "Kirsher, Jeffrey T" , Paolo Bonzini Subject: Re: [RFC][PATCH 01/12 v3] x86/kvm/tracing: Use helper function trace_seq_buffer_ptr() Message-ID: <20141104143538.799e8716@gandalf.local.home> In-Reply-To: <20141104140954.3a31ebe3@gandalf.local.home> References: <20141104155237.228431433@goodmis.org> <20141104160221.585025609@goodmis.org> <20141104140954.3a31ebe3@gandalf.local.home> X-Mailer: Claws Mail 3.10.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.142:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 4 Nov 2014 14:09:54 -0500 Steven Rostedt wrote: > On Tue, 4 Nov 2014 17:17:08 +0000 > "Rustad, Mark D" wrote: > > > On Nov 4, 2014, at 7:52 AM, Steven Rostedt wrote: > > > > > From: "Steven Rostedt (Red Hat)" > > > > > > To allow for the restructiong of the trace_seq code, we need users > > > of it to use the helper functions instead of accessing the internals > > > of the trace_seq structure itself. > > > > > > Cc: Mark Rustad > > > Cc: Jeff Kirsher > > > Cc: Paolo Bonzini > > > Signed-off-by: Steven Rostedt > > > --- > > > arch/x86/kvm/mmutrace.h | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h > > > index 5aaf35641768..ce463a9cc8fb 100644 > > > --- a/arch/x86/kvm/mmutrace.h > > > +++ b/arch/x86/kvm/mmutrace.h > > > @@ -22,7 +22,7 @@ > > > __entry->unsync = sp->unsync; > > > > > > #define KVM_MMU_PAGE_PRINTK() ({ \ > > > - const u32 saved_len = p->len; \ > > > + const char *saved_ptr = trace_seq_buffer_ptr(p); \ > > > > I think the above should not be a const char *, because the location pointed to is surely being changed. It should either be a char * or a char * const. > > Ah right. It should be 'char * const'. > Actually, I take that back. The contents of saved_ptr should not be modified. It may seem strange, but the update is done via the trace_seq_printf(). Then that content is return back to the user. The user should definitely *not* modify the contents of saved_ptr. This patch is good as is. It should not be a char *, or char * const. -- Steve > > > > > > static const char *access_str[] = { \ > > > "---", "--x", "w--", "w-x", "-u-", "-ux", "wu-", "wux" \ > > > }; \ > > > @@ -41,7 +41,7 @@ > > > role.nxe ? "" : "!", \ > > > __entry->root_count, \ > > > __entry->unsync ? "unsync" : "sync", 0); \ > > > - p->buffer + saved_len; \ > > > + saved_ptr; \ > > > }) > > > > > > #define kvm_mmu_trace_pferr_flags \ > > > -- > > > 2.1.1 > > >